1. Field of the Invention
The present invention relates to vehicle lamp systems.
2. Description of the Related Art
Typically, a vehicle lamp can switch between a low beam and a high beam. The low beam illuminates a close range at a predetermined illuminance. Light-distribution patterns of the low beam are regulated so as not to cause glare to oncoming vehicle or leading vehicle, and the low beam is used mainly when the vehicle travels in a city area. Meanwhile, the high beam illuminates a distant, broad front range at a relatively high illuminance and is used mainly when the vehicle travels at high speed on a road with little oncoming vehicle or little leading vehicle. Thus, the high beam provides better visibility for the driver than the low beam does but disadvantageously causes glare to a driver of a leading vehicle or of an oncoming vehicle or to a pedestrian.
In recent years, a technique for dynamically and adaptively controlling a high-beam light-distribution pattern on the basis of conditions surrounding a vehicle has been proposed (see, for example, JP2008-137516). According to this technique, the presence of a leading vehicle, an oncoming vehicle, or a pedestrian is detected, and light in a region corresponding to the detected vehicle or pedestrian is attenuated to reduce glare to the vehicle or pedestrian.
In a vehicle lamp system such as the one described in JP2008-137516, when a predetermined light-distribution pattern that is in the middle of switching in association with a certain event is to be switched to a different light-distribution pattern in association with another even that has occurred after the aforementioned event, the light-distribution pattern is switched with the priority given to a switching time corresponding to the later-occurring event. This may be preferable in terms of simplifying control but leaves room for improvement in terms of the comfort for the driver.